1. Field of the Invention
This invention relates to improvements of body structures of stringed instruments such as electric guitars.
2. Description of the Related Art
Conventionally, various kinds of stringed instruments such as electric guitars are known. The basic configuration of an electric guitar is shown in FIG. 5, wherein a neck 31 is connected to a body 30, and strings 32 are stretched under tension between tuning pegs 33 and a tailpiece 34. Pickups 35 are arranged on the body 30 to detect vibrations of the strings 32, which are converted to electric signals. Herein, electric wiring is arranged such that the electric signals are sent to a volume unit (not shown), which is built in the body 30 and which is varied and adjusted by tone controls 36.
To play music, the player intensely plucks the strings 32 of the electric guitar and operates variable resistor(s) of the volume unit frequently. For this reason, abrasion and mechanical troubles easily occur in electric guitars. The variable resistor is configured such that a sliding member slides on the resistor surface. The resistor surface is easily damaged or abraded if the player operates the variable resistor very frequently. Further, the resistor surface may become oxidized if the user does not operate the variable resistor of the electric guitar for a long time. Abrasion or oxidation of the resistor surface of the variable resistor may cause noise in the sound of the electric guitar. Or, the electric guitar may have problems in which sound signals cannot be output due to imperfect contacts of the variable resistor.
To cope with the aforementioned problems, the electric guitar should be configured such that its electrical parts can be easily replaced with new ones. For example, an electric guitar of a solid type employs a specific structure, a partial exploded view of which is shown in FIGS. 6A and 6B. FIG. 6A shows a body 40 made of the pure wood material. A selected area of a backside of the body 40 is bored to form a hollow portion 41 for arranging electrical parts such as the variable resistor. The opening of the hollow portion 41 is covered with a back cover 42 (see FIG. 6B), which is fixed to the backside of the body 40 by wood screws. Thus, it is possible to easily cope with replacement of the electrical parts by merely detaching the back cover 42 from the body 40.
The present applicant has proposed an electric guitar of a semi-acoustic type, which is disclosed by Japanese Patent Unexamined Publication No. 2000-276167. This electric guitar provides a center block, and a storage portion of electrical parts is made hollow. This raises difficulties in applying the aforementioned structure specially designed for use in an electric guitar of the solid type to an electric guitar of the semi-acoustic type.
Therefore, the electric guitar of the semi-acoustic type employs another type of body structure, an exploded view of which is shown in FIGS. 7A-7D. As shown in FIG. 7B, a center block 52 is placed to engage with a space that is formed between ribs 51 of a body frame 50, which is formed of metal material or synthetic resin. A front board 55 shown in FIG. 7A is adhered to the body frame 50 and the front side of the center block 52. A back board 56 shown in FIG. 7C is adhered to the body frame 50 such that it covers a through hole 53 and the back side of the center block 52.
FIGS. 8A and 8B show a partial exploded view containing perspective illustrations of the prescribed parts of the body structure of the electric guitar. When the back board 56 is adhered to the body frame 50 as shown in FIG. 8B, a through hole 54 is opened to the rear of the body frame 50. There is provided a back cover 57 (see FIG. 8A) whose shape matches with contours of the body frame 50 and rib 51 in connection with the opening of the through hole 54. Fixing the back cover 57 to them by vises (or small screws) 58, it is possible to assemble together all parts of the body as shown in FIG. 9. Herein, the back cover 57 is detachably attached to the backside of the body frame 50, which allows maintenance and replacement of the electrical parts that are arranged inside of the through hole 54 within the body of the electric guitar.
In the aforementioned body structure conventionally employed in electric guitars, the back cover 57 occupies a relatively large area over an entire backside area of the body. This is not preferable in terms of the appearance and sound quality of the electric guitar.
Particularly, the back cover 57 is not adhered but is merely attached to the back side of the body frame 50 by vises 58. This gives rise to problems due to the inappropriate body structure in which resonance easily occur in the guitar""s sound, so it is hard to maintain the stable performance of the electric guitar. In addition, this raises various problems due to reduction of the rigidity of the body structure of the electric guitar.
It is an object of the invention to provide a body structure of a stringed instrument such as an electric guitar in which sound quality, rigidity and appearance are improved by minimizing the area specifically occupied by a back cover covering a storage of electrical parts within the body.
The present invention provides a stringed instrument such as an electric guitar with a specially designed body structure, which is configured by a body frame, a center block, at least one bridge, a front board, a back board and a back cover. The bridge is arranged between a side portion of the body frame and a side wall of the center block, thus partitioning the interior space of the body frame to provide a vacant space for storing electrical parts. Because of the provision of the bridge, it is possible to improve the rigidity of the body structure. Herein, the vacant space is reduced in size and area, and it is encompassed by the side portion of the body frame, side wall of the center block and the bridge. The front board is used to completely cover the front side of the body frame. The back board is partially cut out and is used to cover the back side of the body except for an opening area of the vacant space inside of the body frame. The back cover is detachably attached to the back side of the body frame in conformity with the cutout of the back board. Because the back cover has a restricted size and shape for merely covering the opening area of the vacant space in the backside of the body, it is possible to inhibit the back cover from easily resonating with the sounds produced by plucking the strings of the stringed instrument. Thus, it is possible to improve the sound quality as well as the appearance of the backside of the stringed instrument.
The aforementioned body frame and bridges can be integrally formed together by using metal material or synthetic resin. In addition, it is possible to further provide ribs for reinforcing the body, which are arranged along the side walls of the center block. In that case, the body frame, bridges and ribs can be integrally formed together by using metal material or synthetic resin.